Role of circadian clock in the chronoefficacy and chronotoxicity of clopidogrel
Background and purpose The role of CLOCK in regulation of drug chronoefficacy and chronotoxicity remains elusive. Here, we aimed to uncover the impact of CLOCK and dosing time on clopidogrel efficacy and toxicity. Experimental Approach The antiplatelet effect, toxicity and pharmacokinetics experiments were conducted with Clock −/− and wild-type mice after gavage administration of clopidogrel at different circadian time points. The expression levels of drug metabolizing enzymes were determined by qPCR and Western blotting. Transcriptional gene regulation was investigated using luciferase reporter and chromatin immunoprecipitation assays. Key Results The antiplatelet effect and toxicity of clopidogrel in wild-type mice showed a dosing-time dependent variation. Clock ablation reduced the antiplatelet effect of clopidogrel, increased clopidogrel-induced hepatotoxicity, and blunted their rhythms. This was associated with attenuated rhythms of clopidogrel active metabolite (Clop-AM) and clopidogrel, respectively. We further found that Clock regulated the diurnal variation of Clop-AM formation by modulating the rhythmic expression of CYP1A2 and CYP3A11, and altered clopidogrel chronopharmacokinetics by circadian regulation of CES1D expression. Mechanistic studies revealed that CLOCK activated Cyp1a2 and Ces1d transcription by directly binding to the E-box elements in their promoters, and promoted Cyp3a11 transcription through enhancing the transactivation activity of DBP and TEF. Conclusion and implication CLOCK regulates the diurnal rhythmicity in clopidogrel efficacy and toxicity through regulation of CYP1A2, CYP3A11 and CES1D expression. The findings may contribute to the optimization of dosing schedule for clopidogrel, and deepen understanding of the connection between the circadian clock and chronopharmacology.
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